Art of treating coal-gases.



UNITED STATES PATENT oflantns '1}. acres, or sveac'osn, new roan, ASSIGNOR ro seiner-server commas, or sonvav, NEW YORK, A oonroiaarroiv or PENNSYJLVANIA.

Am or "tamarind consensus.

1,078,014. He Drawing To all whom it may concern:

Be it known that I, CHARLES Gr. Torre, a citizen of the United States, residing at Syracuse, in the county of Onondaga and. State of New York, have invented certain new and useful Improvements in the Art of lreating Ooal-Gases, of which the following is a specification.

As is Well known, gas produced by the destructive distillation of coal contains various elements of value, such as tar, combustible gas which may be utilized for illumi-- nating or heating purposes, and ammonia, both free and in the form of fixed compounds, as well as other substances which "may be classed as impurities. The utiliza-- I tion of the elements of value requires their separation from one another as well as from the accompanying impurities. One method proposed for accomplishing such separation involves the passage of the gas-as it comes from the retort or oven, after separation of the tar therefrom, through sulfuric acid to. convert the ammonia into ammonium sulfate, while the combustible elements of the gas pass on to be separately recovered. The carrying out of such a process, however, presents many practical difliculties owing to the dam r of bringing down with the tar the fixed ammonia compounds, mainly chlorids which are carried in the gasin the form of dispersed salts, and which theneby become mixed with the tar and lost,entailing a Waste of ammonia, which in gases from certain coals mayamount to fort per cent. or more of the total ammonia content. If, on the other hand, these salts are allowed to pass on and be broken up in the formation of the ammonium sulfate, the freed chlorin produces rapid corrosion and destruction of the apparatus with prohibit'ory expense for repairs. In case also the gas is so cooled before the formation of the sulfate as to wholly or partly condense the' water'vapor normally carried by the gas, 5. e. the water vapor derived from the water originally contained in the coal, free ammonia will be brought down in solution and must be recovered by distillation of the ammoni cal liquor thus produced. The naphthalenepresent in the gas has also beena sourcezof I much difli'culty in the methods of treatmentclogging :of t

heretofore em lo'yed, its deposiatntauaxls e apparatus with some catn- Specification of Letters Patent.

Application filed April 19, 1912. Serial No. 891,977.

eflicient and economical process Patented New, iii, friill 1 stopping of the operation and expense for its removal.

The object of my improvements is to ob viate these difficulties and provide a simple, for recovery ing the constituents out loss, and in a commercially pure state To this end I treat the gas as it comes from the receiving main to first remove from it a portion of its tar content and the fixed ammonia compounds in such manner that the fixed ammonia compounds shall enter into solution Without becoming mixed with the tar and thus lost, and without removing. any

appreciable amount of free ammonia. This may accomplish by scrubbing the hot gas as it comes irom the retorts with water or its equivalent, in such quantity as to form a solution of the fixed ammonia compounds, and at such a temperature as will reduce the temperature of the as to a point low'enough to efiect the removal of a portion of the tar and to facilitate the eiiicient removal of the remainder thereof, but not suiiiciently low to cause any appreciable absorption of the free ammonia. l find that at temperatures of from C. to C. this preliminary re moval of the tar and the solution of the fixed ammonia compounds will be efiected without causing the absorption of more than a negligibly small quantity of free ammonia, butl do not limit myseif to the use of this exact range of temperatures since the absorption of an monia slightly greater than the absolute minimum will not seriously afl'ect the coo-- nomic success of the process, and the tar and fixed ammonia compounds may be re-- moved with satisfactory completeness at a temperature slightly above the stated incitimum.

The washing of the gas to remove the fixed ammonia compounds may be accomplished in various Ways that will readily occur to those skilled in the art as by passln [the gas in opposition to a shower of water w 'icii may be circulated repeatedly so thatthe resulting; solution Ina be concentrated to am desired point and lawn oii' as desired.- result may be accomplished by v the hotgas Water vapor in such areas of the amount normally carried tnereb' eat-a portion of it s'ufiic'ient to up area amnesia coiiiptliihds may as removes of value in the gas Withamcanit of free am- "t e s ne adding as temp erunures I The temperature.- conclitions to be observ trace of tar still remains, I inthe following-cord bath and will not be sufficient to impair the commercial value. oi 6k;

vapoix In either case nuclei the temperages, involving the heavier tar constituents,

little bee-i; is generated in the setumi'or, the I oinpeml-ure may even be somewhat raised cooling without absorption of the free amlTlOIlliL, and then coolinglzhc gas so as to conclense such portion of the contained water ture conditions indicated above, the fixed ammonia, not being a true gas, is dissolved and held in solution while the free ammonia passes on unabsorbed. The resultin' solucion may be distilled with lime and the free ammonia- I gas produced united with fillet originally present to form ammonium sulfate, or the liquor may be directly worked for the. recovery of fixed ammonia. salts as such.

Instead; of washin the gas with water to form a solution of tbe fixed ammonia. compounds to be subsequently treated, it may be washed in the first instance with an alkaline solution as of caustic soda, soda ash or other suitable alkali, whereby the fixed ammonia compounds will be broken up and their emmonlu content added directly to .the free ammonia originally present in the gas. By this pi eliminary washing unii cooling a large proportion of ihe tar carried by the is thrown down and the gas is brought into a, condition in which the remaining, lighter, tar can be removed. without further decrease of temperature, and, if requirefi, e. 9,. in cases of a gas so poor in amnwnis that but without interfering with the removal. ofthe bar. In any case ll so proceed that the gas is brought chrough the ncicl bath at' such a temperature that no comiensation of water vapor takes place lliereimnnd the desired reactions are readily and neatly effected,

Since ear cannot; bb efiicienily removecl' from gas by washing; it in water, except at theffrec ammonia, 1. subject the gas, after washing, to dry treatment, a, 6., without COKl-v lensing any of.- the normally contained water vapor, to complete the removal of the our.

are subspentielly as above stated, e be tween (1 and 0. so as to avoid on the one hand ehe condensetion of water vu or (with loss of free ammonia) and depositlon of naphthalene and, on the other hand to most. efliciently effect the removal of the in. This? finel removolgof' one t er before the as enters the acid halal: .umy, subjectto t e above sinicol c'onditicms be effected in any usual or convenient manner as by passing the gas through tar or through chambers containing bafiles and through perforated screens by impact; with which practically the last par ticles of tar ere-removed. In case anysllght shis is removed the ammonium sulfele proclucefi labegrein',

so low as to cause solution of suitable form of apparatus gnu be used for cordingto ch'e deslre of the reference 't'othe' character of Hie 172 The gas efter being treated to be freed from tar is passed through a bat gif sulfurlo acid where combination of the a monic constituent of the gas with the acid takes plaice,

forming ammonium-sulfate, and the com- 70 bustible elements of the guspass on to be subsequently treated and recovered. Up to the point where the combustible elements of the gas leave the acid both, it is maintained at such a temperature that the naphthalene is not deposited. In order to remove'the naphthalene from the gas I wash the gas, after it leaves the acid bath, in water, or other liquid in which naphthalene is insoluble or only slightly soluble, and of such low temperature as to cause precipitation of the naphthalene. Such considerable quantity of water should be employed that; the deposited naphthalene will be in suspension in the water and will be washed out: freely without lodgment. Water of the tempera ture of that of any usual source of supply such as river or s rini-watcr, may be used for. this purpose, t 1011 any lower tempera. time may be employs the lower the tomperature the more raid beinp the recipilav faction of the naphtha ene.. I e ound it possible in this manner to reduce the gas from a temperature of 70 C. to as low as 5 0., and to remove the naphthalene continuously in the form of minute crystals without any tendency whatever for these crystals to cohere and thus plug the apparat-us. The naphthalene after itsprecipitation may be readily-removed from t a water by clecantetion and used in any desired manner.

The residue of gas after theimmovol of the naphthalene may be treated in any well known way for further purification if desired and stored for use as required; 0 i

It will be understood that any well known ouriying my process into -e ect, end the j r, exact temperatures used may be varied I105 ofperetor huving o the gusto be treated, and I do not limit by-inventionin these respects, v I l What I do Iaim as new,- andtdcsire to soi cure by Letters Patent, is z;,- if f l. hog-process-ofztresei gimfg ases to eepamee and recover lheir constituents of; V9.

no, which'cbusislss iii'fi sflgzremovkif' they I solulgion. an the 13 heavier is constituents 'wlthout absorption f 6; W i f" c from 11d convertingthe free ammonia into emm nium sulfate and subse" uenyl -rev movin the naphthulene in crystaorm'fi; .2. e process of treating coal @css' lpfl; sepamfi'eand recover their-constituents of vc ue. -wl 1ich consists "in" first, washingg' tho gee mesmerin such excess dudat suchwmu uu w s tc...l.; wn v t e lben freeingthe'gas. v H

all

monia salts in solution with aportion of then completing the separation-of the tar: from the gas and converting the free ammonia into ammonium sulfate'while maintaining a temperature above that at whichnaphthalene will deposit and" subsequently removing the naphthalene from'the gas in crystalline form. v 1

3. The-process of treating coal gases to separate and recover their constituents 'of value which consists in first removing the fixed ammonia salts in solution with'a'por-j ammonia, then completing, t e separation of the tar from the gas and. converting the free ammonia 'into' ammonium sulfate; flmean: while keeping the gas at such tern erature 'tionof the tar "without absorption of thefree as toprevent the deposition of nap thalene and .fsubsequently removing the naphthalene from the gas by washing t e gas w th a cold 4. The pro ssot va us which consists of approximately from'60 c rom so as to removethe fixed ammonia salts' jin sci-1 I l'u-tion with a E sorption of t e ortion of the tar without ab,-

gas and converting ,theifree ammoniafinto ammonium sulfate without'material change of temperature and subsequently removing the naphthalene from the slightly soluble. 5. 'lhe process of'treating coal gases to separate-and recover their constituents of value which consists in removing the tar and ammonia from the gas at'tem 'eratures above that at which the mi htha ene' will solidify, and then coolin t e gas in the presence of a liquid in which naphthalene" is insoluble or only slightly soluble,-where 7 above that at which the naphthalene will solidify, and; then cooling the as in the presence of a. li aid in which nap ithalene is insoluble or on y slightly soluble,- whereby separate and recovertheir free ammonia then com pleting the separation ofthe; tar from. the

gas .by washing a the gas with a cold liquid in which naphtha-p lone is insoluble or only independent "crystals.

he'naphthalene is tleposited in the form of the tar without absorptiomof .the' free ama- Y monia J or decompositionwof naphthalene,. 7

value which consists in removing the tar and ammoni a from the gas at temperatures solidify; and then. washing liqluid' in which naphthalene ture as to :00

naphthalene.

8. The process of treating coal 'gases to y slightly soluble, and of such temperavalue which consists in removing the tar and ammonia.- from the. gas at temperatures ene W1 above-that at which the na htha solidify, and then washing e gas with a 'li' ind inwhich naphthalene is insoluble or on y slightly solub e, ture' as to cool the as encl' cmise the precipitation of the napht dependent crystals; l

"9.. The process of treating coal gases to separate-and recover their constituents of i value, which consists in cooling the hot gas as-it comes thc main, in thepresence 85 from C.-'to- 70 G.,' whereby a portion of of "an excess of water-to a temperature of the tar and the fixed ammonia'salts are removeditherefrom', then completingthe removal ,ofthe tar and treating the gas with acid to convert the free ammonia m'to ammonium sulfate without material reduction Qf'tem eI-ature; and finally removing the naphthalene from the gas.

'10; The process of treating coal gases to separate and recover their constituents of value which consists in cooling the hot gasas it comes from the main, in-"the presence of an excess of water to a. temperature of 7;.The process' of treating coal gases to separate and recover their constituents of l the. gas. and crystallize the.

alone in the form of 1nconstituents of and of such temper'afrom 60 O. to 70 0,, whereby a ortion .oi

a the tar and thefixed ammonia sa tel-choremoved therefrom, then completing the re ,moval of the tar and treating the gas with I a cid to convert the free ammonia intoflenh monium sulfate,and finall coolin the gas "in the presence of a liqui in which nahthalene is insoluble or-only slightly solu le,v

to remove the naphthalene.

In testimony whereof, I have liereunto subscribed my name, this I'Zth dayflof 'April CHARLES G. TUFTS. I

Witnesses: Fnuonmox W. Firm: H. Duane Bang; v I 

